Sliding bearing having self-lubricating liner

Abstract

The sliding bearing has a metallic outer ring and a self-lubricating liner formed on the inner circumferential surface of the outer ring. The self-lubricating liner has a self-lubricating resin composition consisting of a mixture of 60 to 80% by weight of polyetherketone-based resin, 10 to 30% by weight of polytetrafluoroethylene, 5 to 15% by weight of carbon fiber and not more than 15% by weight of aramid fiber, total amount of the carbon fiber and the aramid fiber being 10 to 25% by weight. The inner circumferential surface of the outer ring has a surface roughness in terms of center line average roughness not less than R a 4.0 μm and a surface roughness in terms of maximum height not less than R max 30.0 μm; and the outer ring and the self-lubricating liner are unified. A method of producing the bearing is also provided.

What is claimed is: 
     
       1. A sliding bearing comprising:
 a metallic outer ring member, and 
 a self-lubricating liner formed on an inner circumferential surface of the outer ring member, the self-lubricating liner being a self-lubricating resin composition comprising:
 60 to 80% by weight of a polyetherketone-based resin, 
 10 to 30% by weight of polytetrafluoroethylene having a molecular weight of not less than 1,000,000, 
 10 to 25% by weight of added fibers consisting of 5 to 15% by weight of a polyacrylonitrile-based carbon fiber, and 5 to 15% by weight of aramid fiber; 
 
 wherein:
 the self-lubricating resin composition contains no graphite, and 
 the inner circumferential surface of the outer ring has a surface roughness in terms of center line average roughness not less than R a  4.0 μm and a surface roughness in terms of maximum height not less than R max  30.0 μm. 
 
 
     
     
       2. The sliding bearing according to  claim 1 , wherein an inner diameter of the outer ring member decreases from an edge part toward an axially central part of the outer ring, and the inner circumferential surface of the self-lubricating liner is cylindrical. 
     
     
       3. The sliding bearing according to  claim 1 , wherein an inner diameter of the outer ring member increases from an edge part toward an axially central part of outer ring, and the inner circumferential surface of the self-lubricating liner is cylindrical. 
     
     
       4. A method of producing a sliding bearing comprising:
 a step of treating a surface of an inner circumferential surface of a metallic outer ring so that a surface roughness in terms of center line average roughness is not less than R a  4.0 μm and a surface roughness in terms of maximum height is not less than R max  30.0 μm, 
 a step of mixing 60 to 80% by weight of polyetherketone-based resin, 10 to 30% by weight of polytetrafluoroethylene having a molecular weight of not less than 1,000,000, 5 to 15% by weight of polyacrylonitrile-based carbon fiber and 5 to 15% by weight of aramid fiber so that the total amount of the carbon fiber and the aramid fiber is 10 to 25% by weight to obtain a self-lubricating resin composition, and 
 a step of injection molding the self-lubricating resin composition to form the self-lubricating liner on the inner circumferential surface of the outer ring; 
 wherein the self-lubricating resin composition contains no graphite.